dict1 = {"zhangsan": 10, "lisi": 13, "zhaoliu": 50}
# 增
dict1["name"] = " 张三"
# 改
dict1["lisi"] = 199
# 查
print(dict1["lisi"])  # 没有的话就报错
print(dict1.get("lisi"))  # 没有的话就返回none
# 删
dict1.pop("lisi")
del dict1["name"]

# 1.逐一显示列表l1 = ["Sun","Mon","Tue","Wed","Thu","Fri","Sat"]中索引为奇数的元素
l1 = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"]
for i, index in enumerate(l1):
    if i % 2 != 0:
        print(i, index)